The undoubted glamour tie of the round will see Cristiano Ronaldo return to Old Trafford for the first time as a player since his departure in 2009, with the first leg on February 13 at Bernabeu before the second leg at Old Trafford on March 5.

The 36-year-old played under Sir Alex Ferguson for five years between 2001-06, scoring 150 goals for the club across all competitions, before moving to Real Madrid and winning La Liga twice within two seasons.

"United or Madrid… Who do I want to win? Played my heart out for them both. Proud to have played for both. #impossible #MayTheBestTeamWin," van Nistelrooy tweeted.

Despite the stature of the two sides, their domestic campaigns are not identical; United are currently top of the Premier League table, six points clear ahead of nearest rivals Manchester City, while Real Madrid sit 13 points behind Barcelona in third.